Propeller-wheel.



No. 808,814. PATENTED JAN. 2, 1906. F. GHIMZAR.

PROPELLER WHEEL.

APPLIOATION FILED APR.12. 1905.

f www* FRANK CHIMZAR, OF ELY, MINNESOTA.

PROPELLER-WHEEL.

No. 808,814. I

Specification of Letters Patent.

Patented Jan. 2, 1906.

Application led April 12,1905. Serial No. 255 ,466.

To all whom it may concern:

Be it known that I, FRANK CHIMZAR, a citizen of the United States, residing at Ely, in the county of St. Louis and State of Minne- Sota, have invented a new and useful Improvement in Propeller-Wheels, of which the following is a specification.

My invention relates to improvements in screw-propellers, as hereinafter described and claimed.

In the accompanying drawings, Figure l is a front elevation of my improved propeller. Fig. 2 is a side elevationof the same, and Fig. 3 is a rear elevation of the same. y

My improved screw-propeller 1 consistsof a straight shaft 2, a long continuous spiral blade 3 of low pitch, and a short spiral blade 4, disposed at the front end of the propeller. The long spiral blade 3 extends continuously between the points a b, located adjacent to the ends of the shaft 2, and being of low pitch its convolutions are comparatively long and spaced at considerable distances apart. Said blade 3 projects substantially radially from the shaft 2 and may be formed integral therewith or secured thereto by any suitable means. The short blade 4c, which is disposed at the front end of the propeller, is similar tothe blade 3 and preferably projects substantially radially from the shaft 2 and in the opposite direction from that in which the blade 3 projects. The blade 4 extends from the point a to the point c, which is a comparatively short distance in rear of the point a, so that said blade 4 is of a length corresponding to that of one-half of one of the convolutions of the blade 3, as will be readily seen upon reference to Fig. 2. By making the blade 3 continuous and of low pitch and by the provision of the short blade opposite to and starting at a point abreast of the front end of the rst convolution of the long blade, making one-half a convolution around the shaft and terminating with lthe first half-convolution of the long blade, the quantity of water taken in at the front end of the propeller is increased.

I am aware that it has been heretofore proposed to provide a propeller of this class with two oppositely -disposed continuous blades disposed in spiral convolutions to extend from end to end of the shaft; but the eect of such blades is disadvantageouaas one to a considerable extent neutralizes the action of the other. By the provision of the short blade terminating with the first half-convolution of the long blade my improved propeller is caused to take in more water at the front end than could be taken in if only one blade were employed, and owing to the short length of the short blade said blade, while eliicient in taking in the water at the front end of the propeller.l does not neutralize the action of the long blade on the water.

My improved propeller may be mounted upon a boat or ship in any desired manner; but I preferably mount the same in or beneath the keel and make the same of substantially the same length as the keel.

I claim- The herein-described screw-propeller comprising a shaft, the long blade forming a continuous lspiral blade of low pitch, having its convolutions extending from end to end of the shaft, and a short blade opposite to and starting at a point abreast of the front end of the first convolution of the long blade, making one-half a convolution around the shaft and terminating with the first half-convolution of the long blade.

In testimony whereofI have signed my name to this specification in the presence of two subscribing witnesses.

' FRANK CHIMZAR. Witnesses:

JOHN CosGRovE, L. J. WHITE. 

